8 th Conference on Air Quality Modeling – A&WMA AB-3 Comments on CALPUFF Implementation Issues

1. 8th Conference on Air Quality Modeling – A&WMA AB-3 Comments on CALPUFF Implementation Issues By Mark Bennett, CH2M HILL

2. CALPUFF Implementation • Reaffirm support for CALPUFF • agreement beneficial • Specific concerns and recommendations • may serve as template for future models • General recommendation for more active EPA oversight

3. General Concerns • Availability of model developments and associated documentation • considerable lag time • Consistency, availability, and quality of mesoscale data sets • Lack of methodology for evaluation of wind fields • Inconsistent guidance from local and federal agencies

4. Official Regulatory Version Concerns • Official version has known errors • Beta version with fixes not official Recommendation • EPA ensure timely maintenance of the CALPUFF code • EPA provide adequate funding for a “point of contact” where questions can be answered reasonably quickly and accurately

5. Users Guide Concerns • Users guide out of date and incomplete • Request for up-to-date and complete Users Guide made at 7th Modeling Conference (June 2000) Recommendation • EPA ensure up-to-date and complete Users Guide corresponding to official version of CALPUFF is available

6. Meteorological Data Concerns • Inconsistent acceptability • No obs vs Obs • MM5 (and which MM5), RUC, ETA • 36 km vs 12 km vs 4 km • Availability • Adequacy • Proposed increase to 5 yrs Recommendations • EPA oversight for consistency and adequacy • EPA should collect and distribute at cost

7. Complex Winds Concerns • Anticipated increased use • Not as thoroughly evaluated Recommendations • EPA should catalogue and make available • possible solicit input from the modeling community • Reactivate Model Clearinghouse

8. AERMOD-like Dispersion Concerns • 8/10/2001 Irwin recommends “AERMOD-like” dispersion • MDISP = 2 (to select similarity sigmas) • MPARTL = 1 (turns on partial plume penetration effects into elevated inversions) • MPDF = 1 (turns on convective pbl dispersion) • Inconsistent acceptability • Not as thoroughly evaluated Recommendations • Clear guidance • EPA should catalogue and make available • solicit input from the modeling community • Reactivate Model Clearinghouse

9. Visibility Analysis Concerns • Most critical use in PSD permitting • EPA defers to FLMs • Most contentious issues • aqueous phase chemistry • ammonia (lacking guidance, data, etc.) • overprediction of nitrates in winter • User frustrations Recommendations • EPA take over guidance for CALPUFF, including visibility • Upgrade aqueous phase chemistry • Regulatory guidance on ammonia, etc. • EPA should catalogue and make available • solicit input from the modeling community

10. Summary • EPA clearly and definitively take over regulatory guidance for CALPUFF • EPA should ensure support and timely “model maintenance,” esp. in light of future non-traditional model approval • EPA actively collect and make available met data, case studies, etc. • EPA reactivate and actively maintain the Model Clearinghouse

11. List of High Priority Items • Official version free from known errors • with associated Users Guides • Visibility • Mesoscale met data sets • Methodology to evaluate CALMET wind fields • Complex wind fields • AERMOD-like dispersion